Reed switching assembly of deformable material

ABSTRACT

An electrical device and method of making same is disclosed wherein a rigid base member is provided for supporting electrical conductive elements and a thermal plastic member heat sealed thereto. A reed relay is described with blades mounted on a rigid ceramic base and hermetically sealed into a switching chamber by a thermal plastic cover member sealed at the periphery to the base member as by heating with a peripheral metal strip or sonic bonding. Localized deformation of the enclosure sets the gap of the contact blade. A blade is positioned in a slanted notch to spring bias the blade against another and the switching blade can be provided with a perforation filled with a previous metal contact material.

United States Patent Jones Jan. 15, 1974 REED SWITCHINGASSEMBLY 0F DEFORMABLE MATERIAL Primary ExaminerRoy N. Envall, Jr. [75] Inventor: James W. Jones, Hollister, Calif. Attorneym'Kafl Llmbach et E [73] Assignee gggifpac ngineermg lnc Hollister ABSTRACT An electrical device and method of making same is [22] Flled' Man 1972 disclosed wherein a rigid base member is provided for [21] Appl. No.: 236,270 supporting electrical conductive elements and a thermal plastic member heat sealed thereto. A reed relay Related Apphcauon Data is described with blades mounted on a rigid ceramic [62] of 7839M 1968' base and hermetically sealed into a switching chamber by a thermal plastic cover member sealed at the periphery to the base member as by heating with a pe- [Zl ripheral metal Strip or Sonic bonding Localized defcm i 152 154. mation of the enclosure sets the gap of the contact l 1200/1 68 6 blade. A blade is positioned in a slanted notch to spring bias the blade against another and the switching blade can be provided with a perforation filled with a [56] uNlTE g s fr xfr gs gierENTs previous metal contact material. 3,348,174 10/1967 Scheidig 335 154 x 7 Claims, 10 Drawing Figures PMENTEDJM :5 mm 3.786; 384

' SHEET 2' OF 3 FIG.8

REED SWITCHING ASSEMBLY- OF DEFORMABLE MATERIAL This is a division of Application Ser. No. 783,912 filed Dec. 16, 1968, now U. S. Pat. No. 3,651,297.

The present invention relates in general to electrical or electronic components and more particularly, to a reed relay assembly.

Presently, dry reed relays that are being marketed consist of a reed switching element installed in a solenoid coil which is in turn installed into a container with suitable electrical terminations and/or leads for use by the customer. Thus, the conventional reed relay is an assembly of separate manufactured parts with a production cost relating to the cost of the several components as well as their assembly.

The object of the present invention is to provide a new electronic device that operates efficiently and trouble-free.

Another object of the present invention is to provide a new reed switching device using a minimum of parts and wherein the device is reliable, subject to a long life, and resistant to shock and heat.

Another object of the present invention is to provide a new electrical device wherein the relative position of certain elements thereof is accurately set after the device has been assembled.

Broadly stated, the present invention is directed to an electrical device formed with a rigid base member such as ceramic for supporting electrically conductive elements and a thermal plastic member heat sealed to the base member for establishing the environment of said electrical conductive elements. The term thermal plastic is used herein and in the accompanying claims tommean a thermoplastic or a therrnosetting material. The rigid base member provides the structural support and means for accurately positioning the electrically conductive elements relative to one another and the thermal plastic member enables establishment of the desired environmental condition for the electrically conductive elements.

In one embodiment the invention is directed to a reed relay wherein switching reeds or blades are provided within he switching chamber of an enclosure wherein the thermal plastic member is heat sealed to the base member around a peripheral portion not only to seal the conductive elements in the enclosure but to fix the conductive elements in the desired location therefor positively established by the rigid base member.

This structure permits integrated manufacture of electrical devices such as relays while still permitting accurate control of parts location. This invention provides a versatile device with a minimum number of parts that are assured of proper assembly, and when assembled form a device that is rugged and not subject to shock and vibration and gives long life.

In accordance with another aspect of the present invention, the thermal plastic member of the assembly is deformed into contact with one of the electrical elements to move that element from a first position to a second position and hold the element in such second position for accurately controlling the relative position of said elements. This aspect of the invention enables assembly of the separate parts of the'device with a minimum of assembly tools and precautions to maintain precise tolerances and critical spacings. The critical spacing can be achieved easily and automatically after the device has been assembled.

Thus, an electrical device is provided with accurately positioned electrical elements and the method of making same is accomplished efficiently and without danger of adversely affecting the integrity of the device previously assembled. The selection of a rigid base member and a flexible member heat sealed to the base member for environmental control enables the production of this device by this method with the desired accurately positioned elements.

In accordance with still another aspect of the present invention, a reed relay of the type previously described is provided with notches in the rigid base member for receiving and positioning the relay blade and with at least one of the notches provided with a bottom surface lying in a plane that intersects another of the blades at an acute angle whereby a blade held in the one notch against the bottom surface thereof can be spring biased against the other blade. With this construction in a reed relay, maintained contact between the two blades is assured when the device is assembled and thereafter. This construction cooperates uniquely with the deformed portion of the thermal plastic member and technique of deformation for establishing the relative position of elements since the spring bias of one blade against the other can vary from device to device. The relative position of elements controlled by deformation of thermal plastic members can provide a gap spacing that varies from device to device but will always switch in response to a certain coil current.

In accordance with still another aspect of the present invention, a reed relay is provided in the form of a double pole double throw switch almost as easily manufactured as a single switch having a ceramic base member provided with two longitudinally extending channels and the blades forming the contacts extending into the channels through notches in the end of the ceramic base member and with the blades fixed in place and sealed within the recesses by a thermal plastic cover member and surrounded by the switch actuating coil. A magnetic gang-blade assembly is provided at each end of the device including a normally open contact blade, a switching blade, and a coil blade which is connected to one end of the coil. Additionally, a nonmagnetic normally closed contact blade is provided at each end of the base member. This construction provides a switching blade assembly which can be assembled by automated machinery and includes a minimum number of parts for economic assembly. By providing specif c notch sizes for certain blades the parts can be assembled in only one way thereby to prevent improper assembly.

In accordance with still another aspect of the present invention, the switching blade assembly in accordance with the last mentioned aspect, includes on each blade exterior of the switching chamber, a portion of reduced thickness which Serves as a heat choke to prevent conduction of undesired heat into the assembly.

In accordance with still another aspect of the present invention, a reed relay is provided with a perforated switching blade which is back filled at the perforation with a precious metal serving as the contact in a dual cantilevered beam mechanical switching device. This embodiment of the present invention enables mass production of reed relays which are assured of long accurate life.

Other objects and advantages of this invention will become apparent when reading the following description and referring to the accompanying drawing in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIG. 1 is an enlarged perspective view of a reed relay constructed in accordance with the present invention.

FIG. 2 is a plan view of the structure shown in FIG. 1 with the cover member removed and certain portions partially broken away.

FIG. 3 is an end elevational view of the device shown in FIG. 2 taken along the line 33 in the direction of the arrows.

FIG. 4 is a longitudinal sectional view of the structure shown in FIG. 2 taken along the line 44 in the direction of the arrows,

FIG. 5 is a longitudinal sectional view of the structure shown in FIG. 2 taken along the line 5-5 in the direction of the arrows.

FIG. 6 is a transverse sectional view of the structure shown in FIG. 2 taken along the line 66 in the direction of the arrows.

FIG. 7 is an enlarged sectional view of the portion of the structure shown in FIG. 4 delineated by line 77.

FIG. 8 is a schematic view illustrating the manner of adjusting the relation of elements of the reed relay.

FIG. 9 is an enlarged perspective view of the structure shown in FIG. 2.

FIG. 10 is an enlarged perspective view of a blade showing another aspect of this invention.

As set forth above, the present invention is broadly directed to an electrical device having a rigid base member for supporting electrical circuit elements and a thermal plastic member heat sealed thereto. This invention can be used with electromechanical switches or relays, electronic components for circuits such as transistors, diodes and integrated circuits, and electrical components such as potentiometers, resistors, and capacitors. In these various embodiments electrical conductive elements are supported on a rigid base member and the thermal plastic member heat sealed to the base member for fixing the conductive elements in place and establishing the desired environment of the electrical conductive elements. For the sake of simplicity the invention will be described by way of illustration with respect to the accompanying drawings as utilized in a dry reed relay or reed switching device and the method of making same.

Referring now to the drawings with particular reference to FIGS. 16 and 9, there is shown a reed relay 8 which has a hermetically sealed envelope 9 containing a switching chamber 10 therein and comprising a base member 11 of a rigid dielectric material such as alumina ceramic which can be injection molded to the desired shape as described in greater detail below and a cover member 12 of a thermal plastic material such as nylon 30 percent glass-filled and injection molded which can be heat sealed to the base member 11, subsequently deformed and fixed in deformed condition for controlling the spacing of electrical elements within the envelope 9 as described in greater detail below.

For electrical conductive elements the relay 8 includes a magnetic gang blade or reed assembly 13 such as of alloy 52 nickel-iron and including a normally open blade or reed 14, a common," swinging or switching blade or reed 15 and a coil or solenoid lead blade 16 each with multi-layered defused electrical contacts such as gold defusedv over nickel plate in a hydrogen furnace. Blades l4, l5 and 16 are all electrically connected together via a common connecting bar 17 outside the switching chamber 10 which bar 17 is trimmed off after the product is completed. Another electrically conductive element 18 is provided in the form of a non-magnetic blade or reed serving as the normally closed blade or relay contact. This can be made of nickel/silver/copper alloy approximately 15 percent nickel, 17 percent silver and 65 percent copper gold plated at the contact region.

A coil or solenoid 19 formed, for example, of polyurethane insulated copper wire is wound around the envelope 9 intermediate at the ends thereof for providing the magnetic field to switch the relay 9, and a cover 20 such as stamped and formed Mu-metal is provided around the coil 19.

The base member 11, being a rigid dielectric, forms the structural support and aligning means for positioning the various blades while electrically insulating the blades from one another. In the particular embodiment illustrated, which is a double pole double throw relay switch, the base member which is an elongated flat member having first and second ends 21 and 22, respectively, and sides 23 and 24 includes a channel 25 located between the ends 21 and 22 and extending across the bottom surface and up the sides 23 and 24 to receive the windings of the coil 19. In the top surface and partially defining the switching chamber 10, the base member 11 is provided with first and second recesses 26 and 27 extending longitudinally from near the first end 21 to near the second end 22 and separated by a dividing rib 28. At each end of the base member a set of rectangular cross section notches is provided opening into the recesses 26 and 27.

The first end 21 of the base member 11 is provided with notches 31, 32, 33, and 34 with notches 31 and 32 communicating with the first recess 26 and notches 33 and 34 communicating with the second recess 27. Similarly, at the second end 22 of the base member 11, notches 36 and 37 are provided communicating with the second recess 27 and aligned with notches 34 and 33, respectively, at the first end 21. Also, at the second end 22, notches 38 and 39 communicate with the first recess 26 and are respectively aligned with notches 32 and 31 at the first end. Notches 33 at the first end and 38 at the second end are slightly wider than the other notches to insure proper assembly of the blades in the notches.

While the present invention is adapted for providing various switching structures, the particular switch illustrated and economically manufacturable by reason of duplication of parts, is a double pole double throw reed relay with one gang blade assembly 13 provided at the first end 22 of the base member 11 with blades l4, l5 and 16 thereof positioned respectively in notches 32, 33 and 34. At the second end 23 of the base member 11, a second gang blade assembly 13! is provided with blades 14., 15 and 16' thereof located in notches 37, 38 and 39, respectively. Normally closed contact blades 18 and 18 are respectively provided in notches 31 and 36 at the first and second ends 22 and 23.

Ledges 35 and 34 are provided in recesses 26 and 27, respectively, adjacent the notches 39 and 34 for sup porting respective coil blades 16 and 16 positioned therein.

Besides being enlarged, notches 33 and 38 are provided with bottom surfaces 33 and 38, respectively,

which are sloped downardly inwardly into the respective recesses so that these bottom surfaces lie in a plane which intersects the normally closed contact blades 18( and 18, respectively, projecting into recesses from the opposite end.

Normally closed contact blades 18 and 18' include enlarged portions 41 and 41 extending laterally within the repective recesses 26 and 27 beneath the adjacent normally open contact blades 14 and 14, respectively, so that at the enlarged portion 41 and 41 the blades 14 and 18 are superimposed as well as blades 14' and 18'.

The superimposed blades 14 and 18 and 14 and 18 have a length typically less than one-half of the length of the respective recesses 26 and 27 to provide a pair of spaced apart contacts between which the switching blades and 15" can be moved. These latter blades 15 and 15' extend substantially the length of the recesses and are cantilevered from their supporting portion at notches 33 and 38, respectively, for movement between closed and open contact positions in response to magnetic fields established by the coil 19.

As illustrated in FIGS. 3 and 9, notches 32 and 37 through which normally open contacts 14 and 14' pass have a depth less than notches 31 and 36 through which normally closed contacts 18 and 18' pass to position the normally closed and normally open contacts in spaced apart to receive the switching blade therebetween. Notches 33 and 38 have a depth between that of notches 32 and 37 and that of notches 31 and 36.

The coil blades 16 and 16' include a length 42 that is doubled back on itself and provided with a tab 43 projecting transversely from the end thereof for passage through an aperture 43 in the base member 11 where the ends of the coil 19 are connected to the tabs 43.

Each of the blades of the gang blade assemblies 13 and 13' includes a portion 45 of reduced width between the blade portion in the notches and within the envelope 9 and the respective connecting bar portions 17 and 17' exteriorly of the envelope. Similarly, the non-magnetic normally closed contact blades 18 and 18' include a portion 46 of reduced width-between the blade portion in the notches and interiorly of the envelope and an exterior enlarged connection portion 47 to which a lead is attached. With this construction the reduced width portions 45 and 46.provide heat chokes for the blade assemblies so that appropriate leads can be soldered to the outside leads without substantial heat being conducted into the reed relay assembly which might have a deleterious effect on the assembly.

This cover member 12 provided over the top surface of the base member 11 for closing recesses 26 and 27 and defining the top of the hermetically sealed switching chamber 10 within envelope 9 is in the form of an extrusion molded, flat plate portion contacting the top surfaces of side members 24 and 25 and rib 28 and includes extensions 51-54 and 56-59 extending into notches 31-34 and 36-39, respectively, above the blades therein to establish a peripheral seal 55 between the cover and base members 11 and 12.

The peripheral seal 55 is established in one of several ways. In accordance with one embodiment of the present invention, an electric current carrying metal layer is selectively coated on either the base member 11, the cover member 12 or both around the peripheral seal and leads which can include one or more of the blades connected thereto for establishing current therein and generation of localized heat thereby heating the thermal plastic to establish a seal between the cover member 12 and the base member 11 and the respective blades as well as a seal between the metal blades and the ceramic base member.

Alternatively, a seal is provided between the base and cover members 11 and 12 and between these members and the blades by application of sonic vibration to the members at the peripheral seal.

As will be appreciated from the description above and with reference to FIGS. 4 and 7, the switching blades 15 and 15 are bent downwardly against the bottom surfaces 33 and 38' of notches 33 and 38 as the base and cover members are sealed together. This bending action on switching blades 15 and 15 spring biases the remote contact ends of these blades against the normally closed contact blades 18 and 18'. Since the switching blades 15 and 15' are formed of magnetic material while the normally closed contact blades are formed of non-magnetic material, conduction of electrical current between the leads 16 and 16' in coil 19 establishes a magnetic field within the envelope 9 whereby the switching blades 15 and 15', being magnetic, are caused to switch into contact with magnetic normally open contact blades 14' and 14, respectively.

It will be appreciated from the above that the envelope 9 of the relay 8 with the respective blades assembled and sealed therewithin can easily be formed by first laying out the base member 11, placing the normally closed contact blades 18 and 18 in the respective notches 31 and 36, placing the gang blade assemblies 13 and 13' in the respective notches at the opposite ends of the base member, placing the cover member 12 on top of the assembled base member and blades, and heat sealing the cover member 12 to the base member 11.

At this stage of the assembly, due to variations in the characteristics of the different materials establishing the spring action of the various blades and the magnetic force required to change the blade from the spring biased, normally closed contact position to the normally open contact position, the spacing between the nor.- mally open and normally closed contact blades typically only approximates the optimum spacing. In accordance with another aspect of the present invention, the assembled electronic device in the form just described can be operated on to set the gap spacing between the normally open and normally closed contact blades for operation with the appropriate operating coil current.

Thus, with reference to FIG. 8, either a current is established between gang blade assemblies 13 and 13 via coil blades 16 and 16' and through a coil 19 that can be wound on the envelope 9 leaving access to the cover member 12 over the nromally open contact blade to set up the appropriate magnetic field between switching blades 15 and normally open contact blades 14 or a standard field is established in this region. Then a portion 56 of the cover member 12 is deformed such as by a heated probe 57 driven thereagainst in the vicinity of the normally open contact blade 14' by a drive mechanism schematically illustrated as a motor 58. As the heated probe 57 depresses the portion 56 of cover member 12, the portion 56 moves into contact with normally open contact blade 14' and begins to move that blade 14' closer to normally closed contact blade 18'. When the normally open contact blade 14' has moved to a position at which switching blade 15 switches to normally open contact blade 14. by reason of the specific characteristics of this blade assembly and magnetic field, movement of probe 57 is halted such as by a switch in the circuit driving motor 58 and opened by a relay connected between blades and 14. Simultaneously, the deformed portion 56 is fixed such as by cooling the probe 57.

By setting the spacing between the normally closed and normally open contacts after the assembly has been completely sealed and in response to electrical reaction parameter of the switching assembly, the switch is adjusted for optimum performance. This method of assembly and a switch produced thereby produce a highly reliable long-life switching assembly produceable with high efficiency and repeatability.

A typical area size for a reed relay of a type described and illustrated is that of a trading stamp.

While the present invention has been described as particularly applicable to a double pole double throw switch, it will be appreciated that the structure of the relay and method of manufacture are equally applicable to switches for reed relays with different contact configuration. Thus, the envelope could include a sigle recess and provide a double pole single throw, single pole single throw or other desired configuration as well as multiple recesses for other desired switching configurations.

Also, while the invention has been described with the normally open blade, swinging blade, and coil blade of each gang blade assembly electrically connected together, it will be appreciated that the blades can be isolated from one another such as simply by cutting off the connecting bar 17.

Additionally, while the invention has been described with reference to the illustrated embodiment as utilizing a single base member and a single cover member so that a minimum number of parts are utilized, either of these members could be replaced by two or more members. For example, the cover member could be formed as two members, the first of which includes projecting portions into the notches of the base and the second of which is simply a flat slab cover member and wherein all the members are sealed together at one time.

In accordance with still another aspect of the'present invention, as illustrated in FIG. 10, extra long-life contacts can be provided for the reed relay assembly previously described by producing a perforation or cutout portion 62 in the switching blade 15" and'filling this cut-out portion with a precious metal 63 such as platinum which would then serve as the making and breaking contact. In the case of the double pole relay described above and illustrated, this metal contact 63 provides the switching contact to both of the poles.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention as limited only by the scope of the appended claims.

I claim: 1. A reed switching assembly comprising, in combination,

a hermetically sealed envelope including a flat rigid ceramic base member having at least a pair of recesses runingv side by side the length thereof with at least a pair of blade receiving notches provided in the periphery of the base member at each end of each recess and a rigid sealing plastic cover member having a periphery mating with the periphery of said base member,

said members sealed to each other;

a blade assembly including a plurality of switching blades each including a portion projecting through said envelope at one of said notches;

and a switch actuating coil wound around said envelope for producing relative movement of blades within said envelope between an open contact position and a closed contact position.

2. A reed switching assembly comprising, in combination,

a hermetically sealed envelope including a flat rigid ceramic base member having at least a pair of recesses running side by side the length thereof with at least a pair of blade receiving notches provided in the periphery of the base member at each end of each recess, and

a rigid sealing plastic cover member having a periphery mating with the periphery of said base member,

said members sealed to each other;

a blade assembly including a plurality of switching blades each including a portion projecting through said envelope at one of said notches; an

a switch actuating coil wound around said envelope for producing relative movement of blades within said envelope between an open contact position and a closed contact position;

one of said notches at one recess including a bottom surface lying in a plane that intersects at an acute angle a blade projecting into said one recess at the opposite end thereof whereby a blade located in said one notch is held against said bottom surface.

3. The reed switching assembly of claim 1 wherein said cover member is deformed into contact with one of said blades to move said one blade from one position when said members are heat sealed together to a different selected position for establishing a desired relative position between said blades.

4. A reed switching assembly comprising, in combination,

a hermetically sealed envelope,

a blade assembly including a plurality of switching blades including portions projecting through said 'envelope,

and a switch actuating coil wound around said envelope for producing relative movement of blades between an open contact position and a closed contact position,

said envelope including a flat rigid ceramic base member having at least a pair of recesses running side by side the length thereof with at least a pair of blade receiving notches provided in the periphery of the base member at each end of each recess and passing a blade therethrough,

a rigid sealing plastic cover member having a periphery mating with the periphery of said base member, said members sealed to each other and to said blades,

said blade assembly including a pair of normally closed blades, one extending through a notch into one end of one of said recesses and the other extending through a notch into the other end of the other of said recesses,

a pair of gang blades as assembled each having three blade elements including a normally open blade, a switching blade and, a coil blade,

one of said gang blades having said normally open blade extending into said one end of said one recess and superimposed above at least a part of one normally closed blade and having said coil and said switching blades extending into said one end of said other recess with the free end of said switching blade in contact with part of said other normally closed blade,

the other gang blade having said normally open blade thereof extending into said other end of said other recess and superimposed above at least a part of said other normally closed blade, and having said coil and switching blades extending into said other end of said one recess with the free end of said switching blade in contact with said part of said one normally closed blade, said coil blade of said one gang blade connected to one end of said actuating coil and said coil blade of said other gang blade connected to the other end of said actuating coil.

5. The reed switching assembly of claim 4, wherein each of said notches of said base member receiving a switching blade includes a bottom surface lying in a plane that intersects at an acute angle the normally closed blade extending into the same recess from the other end thereof whereby the switching blade positioned within such notch is spring biased against such normally closed blade.

6. The reed switching assembly in accordance with claim 4, wherein each of said blades includes a portion thereof outside said envelope of reduced width between the portion extending into said envelope and a portion exterior of said envelope for making electrical connection thereto.

7. A reed switching assembly comprising, in combination:

a hermetically sealed envelope,

a blade assembly including a plurality of switching blades including portions projecting through said envelope,

and a switch actuating coil wound around said envelope for producing relative movement of blades between an open contact position and a closed contact position,

said envelop including a rigid base member having at least one recess running the length thereof with at least a pair of blade receiving notches provided in the periphery of the base member at each end of each recess and passing a blade therethrough,

a rigid sealing cover member having a periphery mating with the periphery of said base member, said members sealed to each other and to said blades,

said blade assembly including a normally closed bladeextending through a notch into one end of said recess, a normally open blade, a switching blade, and a coil blade,

said normally open blade extending into said one end of said recess and superimposed above at least a part of said normally closed blade,

said coil and said switching blades extending into said other end of said recess with the free end of said switching blade in contact with said part of said normally closed blade, and

said coil blade connected to one end of said actuating coil. 

1. A reed switching assembly comprising, in combination, a hermetically sealed envelope including a flat rigid ceramic base member having at least a pair of recesses runing side by side the length thereof with at least a pair of blade receiving notches provided in the periphery of the base member at each end of each recess and a rigid sealing plastic cover member having a periphery mating with the periphery of said base member, said members sealed to each other; a blade assembly including a plurality of switching blades each including a portion projecting through said envelope at one of said notches; and a switch actuating coil wound around said envelope for producing relative movement of blades within said envelope between an open contact position and a closed contact position.
 2. A reed switching assembly comprising, in combination, a hermetically sealed envelope including a flat rigid ceramic base member having at least a pair of recesses running side by side the length thereof with at least a pair of blade receiving notches provided in the periphery of the base member at each end of each recess, and a rigid sealing plastic cover member having a periphery mating with the periphery of said base member, said members sealed to each other; a blade assembly including a plurality of switching blades each including a portion projecting through said envelope at one of said notches; and a switch actuating coil wound around said envelope for producing relative movement of blades within said envelope between an open contact position and a closed contact position; one of said notches at one recess including a bottom surface lying in a plane that intersects at an acute angle a blade projecting into said one recess at the opposite end thereof whereby a blade located in said one notch is held against said bottom surface.
 3. The reed switching assembly of claim 1 wherein said cover member is deformed into contact with one of said blades to move said one blade from one position when said members are heat sealed together to a different selected position for establishing a desired relative position between said blades.
 4. A reed switching assembly comprising, in combination, a hermetically sealed envelope, a blade assembly including a plurality of switching blades including portions projecting through said envelope, and a switch actuating coil wound around said envelope for producing relative movement of blades between an open contact position and a closed contact position, said envelope including a flat rigid ceramic base member having at least a pair of recesses running side by side the length thereof with at least a pair of blade receiving notches provided in the periphery of the base member at each end of each recess and passing a blade therethrough, a rigid sealing plastic cover member having a periphery mating with the periphery of said bAse member, said members sealed to each other and to said blades, said blade assembly including a pair of normally closed blades, one extending through a notch into one end of one of said recesses and the other extending through a notch into the other end of the other of said recesses, a pair of gang blades as assembled each having three blade elements including a normally open blade, a switching blade and, a coil blade, one of said gang blades having said normally open blade extending into said one end of said one recess and superimposed above at least a part of one normally closed blade and having said coil and said switching blades extending into said one end of said other recess with the free end of said switching blade in contact with part of said other normally closed blade, the other gang blade having said normally open blade thereof extending into said other end of said other recess and superimposed above at least a part of said other normally closed blade, and having said coil and switching blades extending into said other end of said one recess with the free end of said switching blade in contact with said part of said one normally closed blade, said coil blade of said one gang blade connected to one end of said actuating coil and said coil blade of said other gang blade connected to the other end of said actuating coil.
 5. The reed switching assembly of claim 4, wherein each of said notches of said base member receiving a switching blade includes a bottom surface lying in a plane that intersects at an acute angle the normally closed blade extending into the same recess from the other end thereof whereby the switching blade positioned within such notch is spring biased against such normally closed blade.
 6. The reed switching assembly in accordance with claim 4, wherein each of said blades includes a portion thereof outside said envelope of reduced width between the portion extending into said envelope and a portion exterior of said envelope for making electrical connection thereto.
 7. A reed switching assembly comprising, in combination: a hermetically sealed envelope, a blade assembly including a plurality of switching blades including portions projecting through said envelope, and a switch actuating coil wound around said envelope for producing relative movement of blades between an open contact position and a closed contact position, said envelope including a rigid base member having at least one recess running the length thereof with at least a pair of blade receiving notches provided in the periphery of the base member at each end of each recess and passing a blade therethrough, a rigid sealing cover member having a periphery mating with the periphery of said base member, said members sealed to each other and to said blades, said blade assembly including a normally closed blade extending through a notch into one end of said recess, a normally open blade, a switching blade, and a coil blade, said normally open blade extending into said one end of said recess and superimposed above at least a part of said normally closed blade, said coil and said switching blades extending into said other end of said recess with the free end of said switching blade in contact with said part of said normally closed blade, and said coil blade connected to one end of said actuating coil. 